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Considering that most meningiomas are pathologically benign, tumors located in the cerebellopontine angle and petroclival area should be reduced as much as possible, and radiation therapy should be administered if necessary. Consequently, relatively good preservation of cranial nerve function and local lesion control can be expected. However, because the lesions are generally located deep, and are surrounded by various important structures, performing surgical procedures is difficult, and careful management of the surgical strategy is important to avoid complications. Surgical outcomes have dramatically improved with the development of skull base and microsurgical techniques. The main surgical approaches for cerebellopontine angle meningiomas and petroclival meningiomas currently include the anterior and posterior combined transpetrosal, anterior transpetrosal, and lateral suboccipital approaches. Furthermore, with the recent developments in endoscopic surgery, minimally invasive surgery for skull base meningiomas has gradually been introduced. In this article, we explain the preoperative checkpoints, selection of the surgical approach, and surgical techniques for the resection of cerebellopontine angle meningiomas and petroclival meningiomas.

Patients with parasellar meningiomas often initially present with visual impairment. Understanding the surrounding anatomy is essential when preparing for surgery of parasellar meningiomas, as this region includes various crucial neurovascular structures. Historically, invasive craniotomy, such as the orthozygomatic approach or zygotomy, has often been attempted to access the region; however, the use of these invasive approaches has become less common, because of the accumulation of anatomical knowledge, as well as the development of surgical techniques and devices, including the endonasal endoscopic approach. Herein, we summarize how we perform surgery for parasellar meningiomas, and outline tips and pitfalls that could be useful for young residents and trainees who are new to the skull base field.

Malignant forms of meningioma, such as atypical and anaplastic meningiomas, commonly relapse. Recently, there have been many reports elucidating the molecular biological mechanisms underlying meningioma recurrence. Tumors with loss of CDKN(cyclin dependent kinase)2A and 2B or lack of the tri-methylation of lysine 27 on histone H3 protein have a particularly high recurrence rate. In general, primary treatment for recurrent meningiomas comprises stereotactic radiosurgery(SRS)or stereotactic radiotherapy(SRT). However, re-operation is recommended for SRS-, SRT-refractory tumors. One of the benefits of reoperation is that it allows tumor control while decompressing the normal tissue, and changing the tumor microenvironment. Another is that it facilitates the acquisition of pathological and molecular genetic information, which can enable clinicians to recommend precision medicine. However, during reoperation, it is often difficult to detach the tumor from the surrounding brain tissue and cranial nerves because of severe adhesion. In cases of malignant meningiomas with multiple relapses, it is important to share the purpose and goal of the surgery with the patients and their families. In other words, which is being prioritized more, a high resection rate or functional outcomes? Furthermore, salvage surgery should also be a consideration.

Most meningiomas are benign, slow growing tumors, which rarely progress to a higher grade. The incidence rate of malignant progression is estimated to be 2.98/1000 patient-year. However, non-skull base location is a significant risk factor for progression. The median time to malignant progression is 4.3 years; however, the cumulative rate of progression approaches a plateau after 10 years. Although radiosurgery does not appear to increase the incidence rate(0.5/1000 patient-year), exact comparisons have been difficult because of differences in study populations. The median time to progression is 7.0 years from initial diagnosis and 5.0 years from radiosurgery. The cumulative rate appears to increase even after 10 years. The risk of malignant transformation after radiotherapy may increase in patients with tumor-prone syndromes, with some controversies regarding patients with neurofibromatosis type 2. Although short term follow-up in patients with meningioma suggests that radiosurgery is safe, there is uncertainty regarding its use in pediatric patients, and those with tumor-prone syndromes.

During surgery for meningioma, basic surgical techniques and strategies required for the removal of the tumor are common, particularly for tumors located superficially, such as convexity, parasagittal, and falx meningiomas. Four basic surgical techniques, including detachment; devascularization; debulking; and dissection should be combined and repeated in appropriate sequence, tailored to the specific conditions of each tumor. This eventually enables the total circumferential dissection of the tumor from the surrounding tissues. It is essential to retract the tumor towards the space created at the tumor center through internal debulking, rather than retracting the normal brain, to avoid damage to the surrounding brain tissue. During surgery for parasagittal meningioma with venous sinus occlusion, it is crucial to preserve the cortical veins that have developed as collateral pathways to prevent venous complications. During surgery for falx meningioma, the selection of a surgical approach including a contralateral approach based on factors such as the development of bridging veins and significant peritumoral brain edema is required. In this article, detailed surgical procedures for convexity meningioma, parasagittal meningioma, and falx meningioma were described focusing on the application of fundamental surgical techniques tailored to each tumor type.

Recent advances in endovascular treatment have improved the safety and efficacy of this procedure, and the number of cases in which preoperative embolization is performed is likely to increase. Preoperative tumor embolization is still a controversial treatment, and as long as it carries a risk of complications, its primary benefit of reducing blood loss during surgery may not be sufficient to justify treatment. We recently reported that preoperative embolization does not significantly increase complications, but may prolong recurrence-free survival. However, currently, tumor embolization is only a preoperative adjunctive therapy, and there is no evidence that it is a stand-alone option for meningioma treatment. Nevertheless, the possibility that tumor embolization alone can promote tumor shrinkage and reduce peripheral oedema has been reported, although the number of cases is small. Further research is needed, but in the future, tumor embolization may become an in-office treatment under certain conditions, such as in cases of poor general condition, multiple meningiomas, recurrent and refractory cases, difficult surgery and cases where re-irradiation is difficult after post-radiation therapy.

The jugular foramen, also known as the foramen magnum, is a highly intricate region of the skull base through which numerous critical blood vessels and nerves traverse. Meningiomas, the most common tumors in neurosurgical pathology, can arise at any location where the meninges are present, posing significant challenges. Meningiomas involving the jugular foramen and sublingual neural tube are particularly notable for their potential to extend from intracranial to extracranial sites, necessitating familiarity with extracranial anatomy, which is not typically encountered in clinical practice. A comprehensive understanding of anatomical characteristics, along with an ample field of view and working space, is crucial for handling the cerebellum, brainstem, and nerves meticulously. The use of surgical support tools such as neuromonitoring and navigation is essential for enhancing the safety of the procedure. Furthermore, preparedness for treatment options, rehabilitation, and adjunctive therapies is vital in the event of neurological symptoms such as those affecting the glossopharyngeal, vagal, or hypoglossal nerves.

Preoperative embolization(POE)of intracranial meningioma is performed worldwide. Although clear evidence of the effectiveness of POE has not been reported in the literature, the technique plays an important role in open surgery, especially for large or skull base meningiomas. The purposes of embolization include: 1)induction of tumor necrosis, resulting in a safer operation, 2)reduction in intraoperative bleeding, and 3)decrease in operative time. Knowledge of the functional vascular anatomy, embolic materials, and endovascular techniques is paramount to ensure safe embolization. Our standard procedure is as follows: 1)embolization is performed several days before open surgery; 2)in cases with strong peritumoral edema, steroid administration or embolization may be performed immediately prior to surgery; 3)patients undergo the procedure under local anesthesia; 4)the microcatheter is inserted as close as possible to the tumor; 5)particulate emboli are the first-line material; 6)embolization is occasionally performed with N-butyl cyanoacrylate(NBCA)glue; and 7)if possible, additional proximal feeder occlusion with coils is performed. The JR-NET study previous showed the situation regarding intracranial tumor embolization in Japan. Endovascular neurosurgeons should fully discuss the indications and strategies for POE with tumor neurosurgeons to ensure safe and effective procedures.

Recent advancements in endoscopic transnasal surgery(ETS)have expanded the application of this technique to meningiomas in the central skull base area, offering a less invasive alternative with a potentially lower physical burden on patients than conventional microscopic skull base surgery. Notably, while ETS allows surgeons to reach tumors without traversing the brain and nerves, thus theoretically reducing the risk of cranial nerve damage, it requires a high level of proficiency to avoid inadequate resection and tumor recurrence. In this article, we discuss the various surgical considerations, including preoperative imaging, surgical setting, nasal cavity expansion, skull base opening, tumor removal, and skull base reconstruction, as general procedures for specific meningiomas. We further describe the concept and details of our multi-layer fascial closure technique for dural repair in ETS, underlining the importance of skilled dural reconstruction in preventing postoperative complications. In conclusion, while ETS for skull base meningiomas presents a promising and less invasive treatment option, its success relies heavily on the surgeon's experience and understanding of the skull base anatomy, stressing the need for careful approach selection.

The need for resection of the meningioma capsule has long been debated and remains controversial. Even the definition of a capsule does not seem to have been established. We described the histopathological findings of the so-called capsule and the necessity for resection, considering tumor cell invasion and recurrence, based on a literature review.

The basics of meningioma surgery are represented in the '4Ds': Detachment, Devascularization, Debulking, and Dissection. When considering the 4Ds, surgical simulation using 3D images is useful, as it allows the surgeon to understand the 3D relationship between the tumor, feeding vessels, and surrounding tissues. However, the hardness of the tumor and the degree of adhesion between the tumor and surrounding tissue are difficult to determine based on 3D images, and must therefore be confirmed using MRI, such as T2-weighted images.

Preoperative simulation for endoscopic endonasal approach(EEA)using computed tomography and magnetic resonance imaging evaluates tumor extension and the relationship between adjacent structure(the pituitary stalk, major vessels, and cranial nerves); therefore, preoperative planning of nasal procedure, skull base bony removal, and cranial base reconstruction are possible. Additionally, three-dimensional(3D)fusion image aids surgeons to visualize intraoperative 3D findings. These preoperative simulations are critical to avoid complications and predict pitfalls perioperatively. However, tumor consistency or adhesion with adjacent structure cannot be predicted but is judged perioperatively, which affects the extent of tumor resection. This manuscript describes important points of preoperative simulation for EEA, especially the transplanum-transtuberculum approach for craniopharyngiomas or tuberculum sellae meningiomas, showing some examples in patients.

We established a unique pre-surgical simulation method by applying interactive virtual simulation(IVS)using multi-fusion three-dimensional imaging data, presenting high-quality visualization of microsurgical anatomies. Our IVS provided a realistic environment for imitating surgical manipulations, such as dissecting bones, retracting brain tissues, and removing tumors, with tactile and kinesthetic sensations delivered through a specific haptic device. The great advantage of our IVS was in deciding the most appropriate craniotomy and bone resection to create the optimal surgical window and obtain the best working space with a thorough understanding of the lesion-bone relationship. Particularly for skull-base tumors, tailoring the procedures to individual patients for craniotomy and bone resection was sufficiently achieved using our IVS. In cases of large skull base meningiomas, our IVS was also helpful preoperatively regarding tumors, as several compartments were achievable in every potentially usable surgical direction. Additionally, the non-risky realistic microsurgical environments of the IVS provided improvement in the microsurgical senses and skills of young trainees through the repetition of surgical tasks. Finally, our presurgical IVS simulation method provided a realistic environment for practicing microsurgical procedures virtually and enabled us to ascertain the complex microsurgical anatomy, determine optimal surgical strategies, and efficiently educate neurosurgical trainees.

While most meningiomas are histologically benign tumors, higher grade meningiomas classified as WHO grades 2 and 3 are not always amenable to the standard treatment. To accurately assess the biological characteristics and prognosis of the tumor, the WHO classification of meningiomas has been continuously revised based on the latest findings. This article describes the recent modifications of the WHO classification of meningiomas. In the 2021 WHO classification, molecular diagnosis was considered more important and it was integrated into the classification as a stand-alone criterion of some subtypes. As for treatment, surgical resection is the mainstay treatment for meningiomas of all WHO grades while the importance of radiation therapy should be emphasized, especially for skull base meningiomas, to balance the surgical risk and for functional preservation. Among the new surgical techniques, endoscopic resection of midline skull base meningiomas has been established over the last decades. In addition, several notable new insights to control high-grade meningiomas based on prospective observational studies are introduced in this article.

The lateral suboccipital retrosigmoid approach is one of the most established approaches for accessing the posterior cranial fossa. In order to expand the surgical field, several extensions, including(1)extended craniotomy(e.g., far lateral, transcondylar, and transsigmoid approaches), (2)additional intradural osseous or bony drilling(e.g., transmeatal and suprajugular approaches), and (3)fissure dissection(e.g., suprafloccular and infrafloccular approaches), have been described. In this report, we introduce our technique for the retrosigmoid approach and review several extensions as illustrated by schwannoma, meningioma, and epidermoid cyst surgeries.

DuraGen ® , an absorbable, engineered collagen-based artificial graft was introduced in Japan in September 2019 for cranial, transsphenoidal, and spinal surgeries. In addition to its efficacy and safety profile, owing to sutureless dural repair, DuraGen ® is widely accepted by neurosurgeons. Direct tenting with DuraGen ® is occasionally required in patients with large dural defects, particularly in cases of tumors adherent to the dura. To overcome this limitation, we introduced a surgical technique for epidural tenting using DuraGen ® . A 78-year-old man with a history of alexia underwent craniotomy for resection of a left temporal lobe metastatic tumor. We completely removed the recurrent tumor, which was strongly adherent to the dura in the middle cranial fossa. A layer of DuraGen ® was used as a subdural underlay beneath the autologous dura to close the wide dural defect. To avoid postoperative epidural fluid collection, we retracted the DuraGen ® from the epidural aspect and interposed several pieces of muscle, which were sutured on the subdural aspect to ensure that the muscle pieces securely plugged the dural defect. We placed an additional overlay of DuraGen ® along the autologous dura. The patient's postoperative course was uneventful without cerebrospinal fluid leakage, tension pneumocephalus, or wound infection. Reoperations for tumor resection, particularly surgical procedures for refractory meningiomas and malignant tumors cause increasing fragility and wide defects of the dura. DuraGen ® placement enables sutureless closure and is less time-consuming. Our technique of epidural direct tenting with DuraGen ® using muscle pieces sutured on the subdural aspect could be useful in patients with significantly large dural defects and can prevent postoperative epidural fluid collection to ensure complete dural sealing.

Meningioma and glioma represent two common primary intracranial tumors. However, the coexistence of these two lesions in the same patient at the same location is rare. Here, we present a case of a fibroblastic meningioma with a secondary glioblastoma occurring at the same location. A 67-year-old woman underwent surgery for a left frontal parasagittal meningioma, and the tumor was subtotally removed. Two years and 11 months after the surgery, the patient had a tumor at the same location with invasion into the adjacent brain, suggesting recurrent meningioma with malignant transformation. The resected tumor was confirmed histopathologically as a glioblastoma. Genetic analysis revealed that the isocitrate dehydrogenase 1 and 2 genes were wild type, and the TERT promoter mutation was detected. The gene analysis suggests that the tumor was a de novo glioblastoma, not a secondary glioblastoma from a lower-grade glioma. (Received April 9, 2020; Accepted May 27, 2020; Published October 1, 2020).

Metastatic meningiomas are extremely rare, and generally have poor prognosis. We report a case of atypical meningioma with good clinical course despite metastasis 9 years after the initial surgery. CASE:A 58-year-old woman visited a nearby hospital with complaints of hemiplegia and aphasia. MRI showed a large left frontal meningioma;she was referred to our department where she underwent a tumor resection(Simpson Grade I). Histopathological finding revealed fibrous meningioma in the prominent part of the tumor. Additionally, a small lesion with high Ki-67 labeling index was identified;therefore, the final diagnosis was atypical meningioma. Nine years postoperatively, a hepatic mass found incidentally and was resected by digestive surgery;a histological diagnosis of metastatic atypical meningioma was established. Thirteen years after the first operation, routine MRI showed enlargement of the local recurrent lesions in the tumor resection cavity. She underwent a reoperation(Simpson Grade I)at our department, and subsequently, discharged without any neurological deficits. Findings were not suggestive of atypical meningioma. Studies report three good prognostic factors in patients with metastatic meningioma-histologically benign primary tumor, long interval between initial diagnosis and metastasis, and asymptomatic metastatic lesion.

Metastatic brain tumors are important complications in the overall management of cancers. We sought to determine the risk of local recurrence and leptomeningeal carcinomatosis(LC)in patients treated with surgical resection and adjuvant radiation therapy. We retrospectively reviewed 173 consecutive patients with metastatic brain tumors managed by surgical resection between 2002 and 2015 in a single institution. Eighty-seven percent of the patients underwent postoperative adjuvant radiotherapy. The median overall survival from surgery was 9.8 months. Thirty of 173 patients(17.3%)developed local recurrence and 14(8.1%)developed LC following surgery. Male sex(hazard ratio(HR): 2.8, 95% confidence interval(CI): 1.0-10.0), colon cancer(HR: 6.5, 95% CI: 2.2-24.2), and no postoperative radiation(HR: 5.6, 95% CI: 2.1-13.7)were identified as risk factors of local recurrence in multivariate analysis. Female sex(HR: 4.4, 95% CI: 1.2-20.9)and recursive partitioning analysis(RPA)class 3(HR: 1.0e+9, 95%CI: 1.7-)were identified as risk factors of LC in multivariate analysis. Our retrospective review showed that individualized treatment with surgical resection followed by adjuvant radiation therapy is a safe and feasible method to control metastatic brain tumors in the real world.

We present a rare case of supratentorial meningeal melanoma associated with ipsilateral nevus of Ota, and a review of the literature. The patient was a 32-year-old man with a right-sided nevus of Ota, presenting with unconsciousness. His CT and MRI scans revealed an extra axial tumor with dural tail signs; no lesion was detected on systemic examination. Intraoperatively, the tumor demonstrated black hyperpigmentation and was histologically diagnosed as malignant melanoma. Following surgery, he received radiotherapy and chemotherapy. For over a year and a half, the patient has shown no recurrence of the lesion.

We report a case of foramen magnum meningioma manifesting as hypoglossal nerve palsy. A 72-year-old woman presented with progressive hypoglossal nerve palsy and lingual atrophy on the left side. Gadolinium-enhanced T1-weighted magnetic resonance imaging revealed a heterogeneously enhanced mass lesion with dural tail sign partially extending into the hypoglossal canal. The transcondylar approach was performed to expose the hypoglossal canal and resect the tumor completely. Histological examination revealed a transitional meningioma. The postoperative course was uneventful. Hypoglossal nerve palsy improved gradually after the operation.

Purpose: Small meningiomas causing hydrocephalus without obstruction of the ventricular system are rare. Herein, we report a case of small clinoidal meningioma with communicating hydrocephalus, which resolved after tumor removal., Case Presentation: A 70-year-old woman presented with a 1-month history of memory disturbance followed by gait disturbance. MR images revealed a right clinoidal meningioma, 2 cm in diameter, and dilatation of the ventricles suggesting communicating hydrocephalus. The cerebrospinal fluid(CSF)pressure was 130 mmH 2 O, as determined via a lumbar puncture. High concentrations of protein(65mg/dL)were detected in the lumbar CSF. The tumor was completely removed via a frontotemporal craniotomy. Higher protein concentrations(94mg/dL)were detected in the CSF obtained intraoperatively from the sylvian cistern. The histopathological diagnosis was meningothelial meningioma. The patient's symptoms improved markedly after surgery. Postoperative MR images revealed resolution of the hydrocephalus. The lumbar CSF protein concentration returned to normal(43mg/dL). Neither tumor recurrence nor progression of hydrocephalus has been observed for 4 years., Discussion: Communicating hydrocephalus, associated with a small meningioma at the supratentorial region, has not been described. Previous studies have shown that patients with meningioma may develop communicating hydrocephalus after tumor removal or stereotactic radiosurgery. Thus, it is interesting that the small supratentorial meningioma in our case developed communicating hydrocephalus without any therapeutic intervention. Considering the CSF protein concentration, we speculate that the hydrocephalus was the result of CSF malabsorption associated with high CSF protein concentration and CSF pathway obstruction at the suprasellar cistern caused by the tumor.

Leptomeningeal metastasis is a rare entity and its diagnosis is often difficult. Moreover, evidence-based therapeutic strategies have not yet been established. A 52-year-old woman presented with high fever and was diagnosed with bacterial meningitis at first examination;although her fever was alleviated, she experienced motor weakness in both of her lower extremities. Ga scintigraphy highlighted the hot-spot areas of the disease in the cranial bone. She was then transferred to our department. Open biopsy of the skull showed metastasis of the cancer. Chest CT results indicated right breast cancer and Gd-DTPA imaging showed obvious enhancement of the pia mater around the conus medullaris and cauda equina. However, cerebrospinal fluid(CSF)cytological examination did not show the presence of any positive cells;consequently, mastectomy was performed in the thoracic surgical department. The severity of paraparesis and pain in her legs increased;however, repeat MRI 1 month later showed no evidence of any change. Therefore, we performed biopsy of the cauda equina and arachnoid lesions. The pathological diagnosis was metastasis of breast cancer with positive human epidermal growth factor receptor 2(HER2)immunological staining. The results of a repeat cytological examination of the CSF during the surgery were negative. Local radiotherapy(25 Gy/5 Fr)as a monotherapy was selected for the patient, because her family did not approve of the combination of radiotherapy and chemotherapy. The severity of both paraparesis and limb pain decreased immediately after the radiotherapy.

A 59-year-old woman was admitted with to our hospital with a sudden severe headache that had lasted for 5 days. Neck stiffness was present, but no other neurological deficits were present. Subarachnoid hemorrhage and intra-tumor hemorrhage were not noted on a head computed tomography (HCT). The patient's cerebrospinal fluid was xanthochromic. Magnetic resonance imaging (MRI) demonstrated a gadolinium-enhanced tumor with hemorrhagic changes around the foramen magnum. After conservative therapy, MRI showed a decrease in tumor size and a dural tail sign. This tumor was diagnosed as a hemorrhagic meningioma, and was resected with a posterior suboccipital approach. Histology confirmed that this tumor was a benign transitional meningioma with hemorrhagic change. This is a rare case involving benign meningioma onset by hemorrhagic change. Postoperative tumor recurrence was not present.

Here, we report a case of dural cavernous angioma. A 54-year-old man presented with headache in his right frontal area for the previous few weeks. Computed tomography (CT) and magnetic resonance imaging revealed a well-demarcated extramedullary mass, 3 x 2.5cm in size, within the subdural space at the right frontal region. The mass was not enhanced on a contrast-enhanced CT scan, and heterogeneously enhanced after administration of Gd-DTPA on magnetic resonance images. Cerebral angiography revealed an avascular mass. Right frontal craniotomy was performed. On surgery, the mass was found to be mainly extramedullar, and partially intramedullar. No adhesion between the mass and the overlying dura was observed. It was removed in an en bloc fashion. The pathological diagnosis was cavernous angioma. The patient's headache was resolved soon after surgery. Cavernous angiomas are usually intramedullar in the subcortical white matter of the cerebral hemispheres;extramedullary cavernous angiomas are rare. Extramedullary dural cavernous angiomas located in the subdural space at the cerebral convexity are extremely rare. They usually present with headache or mass signs, and resemble meningioma radiologically. During surgery they are easily resected with minimal blood loss. Dural cavernous angiomas should be considered in the differential diagnosis of intradural extramedullary mass at the cerebral convexity.

We report the utility of a pulsed water jet device in meningioma surgery. The presented case is that of a 61-year-old woman with left visual disturbance. MRI demonstrated heterogeneously enhanced mass with intratumoral hemorrhage, indicating sphenoid ridge meningioma on her left side. The tumor invaded the cavernous sinus and left optic canal, engulfing the internal carotid artery in the carotid cistern and encased middle cerebral arteries. During the operation, the pulsed water jet device was useful for dissecting the tumor away from the arteries since it was safe in light of preserving parent arteries. The jet did not cause any vascular injury and did not induce vasospasm as shown by postoperative symptomatology and MRIs. With the aid of pulsed water jet, we could achieve total resection of the tumor except for the piece within the cavernous sinus. The patient had no new neurological deficits after the operation. We consider the pulsed water jet as a useful device, especially when the need to dissect meningioma from parent arteries exists. The jet can help neurosurgeons simultaneously achieve tumor resection and preservation of blood vessels.

Objective: Surgical treatment of paraclinoid tumors adjacent to important anatomical structures, such as the optic nerve, optic chiasm, pituitary stalk, and internal carotid artery, should emphasize maximum resection and preservation of visual function. Thus, early localization and exposure of the optic nerve, and complete mobilization and decompression of the optic nerve and internal carotid artery, are necessary in order to prevent intraoperative neurovascular injuries. However, this technique requires wide exposure of the optic-carotid space through the interpeduncular cistern. We have developed an extradural temporopolar approach for resection of paraclinoid tumors, which can also allow early devascularization of arteries that feed the tumors. We evaluated the surgical outcomes of this approach, paying special attention to clinical and visual outcomes., Patients and Methods: Thirteen patients(4 men, 9 women;24-78 years, mean age 54 years), underwent tumor removal using an extradural temporopolar approach between March 2000 and April 2013. We retrospectively reviewed medical charts, radiological findings, intensive care unit flow sheets, and surgical records., Results: Histological diagnoses included craniopharyngioma(4 cases), pituitary adenoma(3 cases), medial sphenoid ridge meningioma(2 cases), tuberculum sellae meningioma(2 cases), trigeminal neurinoma(1 case), and malignant epidermoid(1 case). Tumors were 1.5-6.0cm in length(mean 3.2cm). Tumors were cystic in all 4 craniopharyngiomas and solid in the other 9 cases. Preoperative neurological deficits included visual disturbance in 10 patients, double vision caused by oculomotor nerve palsy in 2 patients, and vertigo in 1 patient. Additional orbitozygomatic craniotomies were performed in 8 patients. Total tumor removal was performed in 7 patients and subtotal removal performed in 6. The pituitary stalk was microscopically preserved in all patients. Postoperative complications included transient diabetes insipidus in 2 patients, chronic subdural hematoma in 1 patient, and abducens palsy in 1 patient. All complications were completely resolved. Surgical outcomes on discharge were recorded as follows:good recovery(11 patients), moderate disability(1 patient), and severe disability(1 patient, who suffered preoperative consciousness disturbance). Visual outcomes were improved in 7 patients, unchanged in 5, and worsened in 1, with recurrence., Conclusions: The present extradural temporopolar approach, which allows early decompression of the optic nerve, and early devascularization and detachment of the tumor, may lead to greater tumor resection and improved visual outcomes in patients with paraclinoid tumors.

Here, we describe a case with a transverse-sigmoid sinus(TSS)dural arteriovenous fistula(DAVF)with sinus occlusion at its proximal and distal ends;the TSS DAVF turned symptomatic after removal of a coexisting symptomatic sphenoid ridge meningioma. The patient was a 70-year-old man presenting with decreased daily activities and mentation due to dysphasia. Magnetic resonance imaging revealed a large, left sphenoid ridge meningioma. Angiography revealed a tumor stain and a coexisting left TSS DAVF with sinus occlusion at its proximal and distal ends. Cortical venous reflux(CVR)into the temporal veins was observed. After successful tumor removal, the superficial middle cerebral vein was arterialized intraoperatively. However, the patient showed worsened consciousness and dysphasia after the operation. Repeated angiography revealed CVR into the superficial middle cerebral vein through a sphenopetrosal sinus. Transvenous embolization was performed via the contralateral inferior petrosal and intercavernous sinus, which allowed access to the ipsilateral superior petrosal sinus(SPS);the procedure successfully eliminated CVR, while preserving the SPS. The patient demonstrated full recovery. This case exemplifies a coexisting TSS DAVF after tumor resection, and superficial middle cerebral vein decompression due to the sphenopetrosal sinus, an alternate drainage pathway for the superficial middle cerebral vein.

Charles Bonnet syndrome is a condition characterized by visual hallucinations. These simple or complex visual hallucinations are more common in elderly individuals with impaired peripheral vision. The current report describes a case of transient Charles Bonnet syndrome appearing after the removal of a meningioma. The patient was a 61-year-old man who already had impaired visual acuity due to diabetic retinopathy. Brain MRI revealed a cystic tumor severely compressing the right occipital lobe. Starting on day 2 postoperatively, the patient was troubled by recurring visual hallucinations involving people, flowers, pictures, and familiar settings(the train and a coffee shop). These continued for 3.5 months. This period roughly coincided with the time for the occipital lobe to recover from the compression caused by the tumor, a fact that was confirmed by several MRI scans. ¹²³I-IMP SPECT performed 1 month after the surgical operation showed an area of hypoperfusion in the right parieto-occipital lobe. Based on the patient's clinical course and MRI findings, the mechanism of onset of visual hallucinations in this patient was put forward. The release of pressure in the brain by tumor removal and subsequent recovery changed the blood flow to the brain. This triggered visual hallucinations in the patient, who was already predisposed to developing Charles Bonnet syndrome because of diabetic retinopathy. This case is interesting since it indicates that central neurological factors, as well as visual deficits, may induce the appearance of visual hallucinations in Charles Bonnet syndrome.

Here, we report a case of primary intracranial tumor in a chronic hemodialysis patient in which neurosurgery was successful. A 50-year-old man who had been on hemodialysis for 4 years was admitted to our hospital with general fatigue. Neurological examination on admission revealed mild restless. Computed tomography and magnetic resonance imaging performed on admission revealed a large (55 mm×40 mm) tumor mass in contact with the falx. The size of this tumor rapidly increased over the next month. 201Thallium-chloride single photon emission computed tomography revealed abnormal uptake in the same location as the lesion. This suggested a malignant brain tumor and surgical excision was scheduled. Two weeks prior to surgery, frequent hemodialysis was performed using nafamostat mesilate instead of heparin to prevent bleeding and to maintain electrolyte balance, and red cell concentrates and erythropoietin were administered for the improvement of anemia. A triple lumen catheter was inserted in the right internal jugular vein in preparation for emergency continuous hemodiafiltration to maintain homeostasis of circulatory dynamics. Surgery was completed without incident and the tumor was resected totally. During surgery, cerebral edema was well controlled by hyperventilation and a slightly upturned head position. Histopathological examination of the specimen confirmed atypical meningioma. Continuous hemodiafiltration was performed for 24 hours after surgery, and hemodialysis was initiated on the third day after surgery. The postoperative course was uneventful. Three weeks after surgery, the patient was discharged with no neurological deficit and resumed his daily life on maintenance hemodialysis.

We report a rare case of a meningioma causing acute hematoma. A 67-year-old woman presented with sudden headache. No evidence of trauma was seen. CT demonstrated a subdural hematoma in the convexity of the fronto-temporal lobe. Magnetic resonance imaging showed marked signal heterogeneity in the convexity of the frontal lobe. One week later, the patient underwent hematoma evacuation and tumor resection including the attached dura mater. The histological diagnosis was meningothelial meningioma. The clot was connected directly to the tumor and the origin of the subdural hematoma was identified as the meningioma. Postoperative course was uneventful, and the headache improved. Meningiomas have a relatively benign course but rarely present with hemorrhage. Surgical exploration is the effective and recommended treatment.

We describe a 30-year-old female with intractable symptomatic epilepsy caused by an insular calcified mass, which was histologically proved as psammomatous meningioma. Seizures were described as consciousness impairment, motionless stare and automatism. After total removal of the tumor with a neuronavigation system and motor evoked potential (MEP) monitoring, seizures completely disappeared without neurological deficit. We emphasize that insular meningioma presents complex partial seizures which mimic medial temporal lobe epilepsy and seizures are controlled by total resection of the tumor.

Background: In the surgeries of the upper part of the cerebellopontine angle (CPA), the petrosal vein (PV) is an obstacle, and the resection of the PV sometimes causes postoperative complications such as cerebellar hemorrhagic infarction. On the other hand, it can be an anatomical landmark during the surgery. We have used three-dimensional (3D) CT images for preoperative evaluation. We, herein, report 4 cases of CPA lesions., Method: The PV was imaged with neighboring structures using CT and a workstation. We paid attention especially to the vein of the cerebellopontine fissure (VCPF)., Result: The four cases include one case of trigeminal neuralgia, two meningiomas and one case of acoustic schwannoma. 3D CT images showed (1) the anatomical formation such as course of the PV, (2) relationship to the neighboring structures of the tumors, (3) expectation of complications after sacrificing the PV. By observing the preoperative 3D CT images, we were able to plan safety operative approaches and procedures., Conclusion: 3D CT images of the PV are very useful for preoperative evaluation of surgery in CPA lesions.

A 34-year-old female presented with an 8-year history of temporal lobe epilepsy. Magnetic resonance imaging showed a multilobular, well-demarcated and homogeneous tumorous lesion of 5 cm in diameter deep in the left sylvian fissure. Intraoperative findings revealed that the tumor was mainly in the left insular region without dural attachment and strongly adhered to the left middle cerebral artery and its perforators. The histopathological diagnosis was transitional meningioma without malignancy. There are few reported cases of deep sylvian meningioma without dural attachment. We review the literature and summarize the clinicopathological characteristics of this condition.

A 72-year-old man presented with gait disturbance and right homonymous hemianopsia. Magnetic resonance (MR) imaging showed a solid mass around the left cavernous sinus with rostral development of a multi-lobulated cystic component. The tumor was totally removed including the cystic wall via the left transsylvian approach with orbito-zygomatic craniotomy. Most of the tumor was attached to the lateral wall of the left cavernous sinus. Histological examination showed a meningioma WHO grade I with meningothelial meningioma formed lobules with intranuclear inclusions. His neurological symptoms disappeared immediately after the operation. Postoperative MR imaging revealed total removal of the tumor including the large cystic component.

Meningeal melanocytomas are uncommon intracranial tumors and extremely rare in the cerebellopontine angle (CPA). The tumors are generally considered to be benign because they lack malignant features in histological examination, but several literatures describe malignant behavior of the tumors such as high frequency of local recurrence, malignant transformation with leptomeningeal seeding. We describe a case of meningeal melanocytoma in the CPA and discuss the features of the tumor. The case was a 43-year-old woman with a right CPA exta-axial mass suffering from vertigo and nausea. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a mass in the right CPA. The mass was hyperintense on T1-weighted images and hypointense on T2-weighted images. Surgical removal was done and pathological diagnosis was made as meningeal melanocytoma. Twenty months after the first surgery, MRI revealed local recurrence of the tumor and subtotal resection was performed.

Our therapeutic strategy for the petroclival meningioma (PCM) allows for observation for asymptomatic and microsurgery for symptomatic cases. For evaluation of this strategy, functional status assessed by the Karnofsky Performance Score (KPS) in each group was retrospectively analyzed. The records of 29 patients with PCMs were reviewed. Fifteen patients were enrolled in the observation group and the median follow-up period was 40 months (range, 5-170). Eighteen patients underwent operative procedures for resection of PCMs and the median follow-up period was 65.5 months (range, 9-194). In the observation group, 60% of the cases showed radiological tumor growth during the follow-up period. There was functional deterioration in 47% of the cases. The growing tumors were unpredictable. In the microsurgery group, gross tumor resection was accomplished in 22% of the cases. The surgical morbidity rate, a KPS less than 80, at three months after surgery and at the time of the last follow-up was 56% and 6%, respectively. Postoperative KPS at three months after surgery was significantly worse than preoperative KPS. However, most of the patients with a worse KPS had recovered at the time of the last follow-up and they had a favorable functional outcome. Regarding the degree of the KPS change, there was no significant difference between the observation and the microsurgery groups during the follow-up periods. Based on the functional outcomes of each group, our therapeutic strategy for PCMs was shown to be reasonable and warranted.

We report the case of a 64-year-old woman with cystic meningioma; this patients was otherwise healthy and experienced formed visual hallucinations after excision of the tumor. She experienced diplopia associated with metamorphopsia, which had persisted for 5 years only when she laid down and turned on her left side. After the excision of the convexity meningioma located in the right temporoparietal lobe, she experienced several types of formed visual hallucinations such as closet-like pictures, flowers sketched on stones, falling maple-like leaves, and moving or wriggling dwarves. She was alert and her visual field was normal; further, she did not experience delirium or seizures. She experienced these hallucinations only when she closed her eyes; these hallucinations persisted for 3 days after the operation. The patient illustrated her observations with beautiful sketches, and the mechanism of visual hallucinations was studied.

Intracranial extraskeletal mesenchymal chondrosarcoma is a very rare tumor that affects young adults. We report a 31-year-old woman with a huge intracranial extraskeletal mesenchymal chondrosarcoma. She presented with a history of right homonymous hemianopsia for 6 months. Computed tomography scans demonstrated a heterogeneously enhanced mass, in the right occipital region, which was lobulated and contained areas of calcification. Magnetic resonance imaging demonstrated a large mass (67 mm) of heterogenous intensity that showed enhancement and was attached to the falx cerebri. The patient underwent right occipital craniotomy and subtotal removal of the tumor. At operation, the tumor was found to arise in the falx cerebri and the cranial vault was not involved. Pathologic examination revealed a mesenchymal chondrosarcoma. She underwent conventional radiotherapy after surgery and remained free of progression at the 20-month follow up. We review previously reported cases of extraskeletal intracranial mesenchymal chondrosarcoma and discuss imaging diagnosis, treatment strategies, and outcome.

Objective: To analyses the result of linac radiosurgery (LRS) for the treatment of intracranial benign lesions and to assess possible factors related to complications., Methods: The authors retrospectively reviewed 204 patients treated with LRS between May, 1993 and December, 2003. The study determined the correlation between radiosurgical complications including imaging changes after LRS and multiple factors such as radiosurgical parameters, location, volume and shape. We divided the patients into three groups by MRI imaging changes and clinical symptoms. Group 1 (Gr. 1): Imaging change only. Group 2 (Gr. 2): Imaging change with transient symptoms. Group 3 (Gr.3): Imaging change with permanent symptoms., Result: Ninty-three patient with AVM: Gr. 1, 8 cases (8.6%), Gr. 2, 1 case (1.1%), Gr. 3, 2 cases (2.1%). A significantly higher incidence of imaging change was noted in patients with arteriovenous malformation (AVM) volumes greater than 10 cc, irregular shape of the nidus and deep location. Fifty-eight patients with vestibulan schwannoma (VS): Gr. 1, 6 cases (10.3%), Gr. 2, 1 case (1.8%), Gr. 3, 2 cases (3.4%). Imaging changes were seen mostly in cases with tumor volume greater than 5 cc. Fifty-three patients with meningioma: Gr. 1, 4 cases (7.5%), Gr.2, 2 cases (3.7%), Gr.3, 0 case. Imaging changes were seen mostly in convexity, parasaggital, and falx meningiomas that were deeply embedded in the cortex. The symptom continued the until last serial observation in four cases. We used various interventions in these patients including steroid, anticoagulant, surgical removal, and hyperbaric oxygen therapy; but these therapies were not effective., Conclusion: LRS for each disease seems to be a safe and effective treatment. However, once serious radiation injuries occur there is no effective therapy, so it is important to make appropriate selection of patients for radiosurgery.

A 64 year-old woman with a diagnosis of lung adenocarcinoma was admitted to our neurosurgical division in February, 2007, suffering from severe headache and dizziness. Systemic chemotherapy had been repeated for multiple metastases to the bone and cerebral cortex since 7 months before. Reexamination with MRI revealed mild hydrocephalus without cortical metastasis. Cytological analysis of the cerebrospinal fluid (CSF) provided the diagnosis of leptomeningeal metastasis. Removal of 8 ml of CSF dramatically alleviated the patient's symptoms. To improve the quality of her remaining life, she underwent lumboperitoneal (L-P) shunt using a Strata adjustable pressure valve. Severe headache disappeared and other symptoms gradually improved after the operation. She survived for 10 months after the shunt placement, perticipating in family life for 6 months. Pressure level of the Strata valve was changed twice according to the degree of hydrocephalus and functioned well while her life lasted. The present case showed that L-P shunt is one of the effective palliative procedures and an adjustable pressure valve is available for this kind of CSF shunt in patients with leptomeningeal metastasis.

Conventionary, we use 5-aminolevulinic acid (5-ALA) for photo-dynamic diagnosis in the removal of malignant gliomas. 5-ALA is converted to protoporphyrin IX (PpIX) in the body and emits red fluorescence, with the excitation of blue-violet light. As PpIX preferentially accumulates in the tumor tissue in comparison with normal tissue, this red fluorescence becomes a good hallmark for discrimination between normal and tumor tissues, especially in malignant gliomas, which have infiltrative characteristics. Approximately 80% to 90% of the malignant gliomas show this red fluorescence in surgery as mentioned above, while only a limited number of metastatic brain tumor cases do. In the surgery for metastatic brain tumor and lesionectomy for radiation necrosis and neurodegenerative disease, white matter around the lesion showed vague fluorescence, which also provided us with a hallmark in the surgery. Additionally, in meningioma, some tumors showed the red fluorescence, which is especially helpful in the removal of the infiltrative portion in the bone and normal parenchyma. In this paper, we also discuss high quality international reserch on 5-ALA-guided surgery for malignant gliomas. The most important point in 5-ALA-guided microsurgery is the use of good equipment that can provide sufficient operative fields even under fluorescence mode.

A 50-year-old female, who had a headache after Eustachian tube insufflation for her ear congestion, came to our hospital. CT and MRI revealed pneumocephalus and petrous ridge meningioma which destroyed petrous bone and air cells. Eustachian tube insufflation was considered to make the air coming into the middle ear, mastoid air cell and then into the intracranial space destroying the tumor. At surgery, there was subdural hematoma around the tumor. Total removal of the tumor and the hematoma membrane was performed. Histologically, the tumor was transitional meningioma and the cluster of meningioma cells were noted in the subdural hematoma membrane.